Applied Mechanics and Materials Vols. 110-116

Abstract: We have proposed a modified traffic model in which a single car moves through a sequence of traffic lights controlled by a step function instead of a sine function. We have found the complex behaviors in this simple traffic model and given three kinds of bifurcation diagrams. We have found that in this model there are chaotic and complex periodic motions, as well as special singularity. In this paper, we will introduce two special kinds chao which is different from general chao and the singularities of the simple traffic model. There are three different kinds of singularity which are single singularity, unsymmetic and symmetic double singularity.

Abstract: Determination of methylene blue concentrations of hydrogen sulfide in the air is sensitive and rapid ect. However, the standard curve tend to appear low line slope, leading to measurement errors. In the preparation of ZnS colloidal process, it is nitrogen as the carrier gas and protective gas. Its direct impact on the ventilation conditions colloidal particle size and uniformity of the precision for the calibration concentration have the significant impact, particles size appropriate uniform colloidal solution and the concentration can be more stable and accurate calibration by the standard curve. It was drawn to meet the requirement that is possible, too large or too small particles on the experimental results will lead to a greater impact. This article is related to the verification experiment of nitrogen ventilation conditions (uniform or not) with aeration velocity on the slope of the curve standard. The experiment we have come to: In this study, ZnS colloidal preparation on passing the nitrogen should be uniform, and the ventilation rate is smaller and needed to continuously bubbling one by one, in which the case of the experimental results, it is required by the standard curve that is drawn 0.1489, spiked recovery rate of 97.5% and 99.0%.

Abstract: Er Lang Shan tunnel is the most absolute altitude constructed highway tunnel in china, which is firstly used the semi-transverse ventilation system, is characteristic of extensive length, higher absolute altitude, multivariate climate, two-way traffic and complex wind stream. Based on FEM software CFDesign, the distributed losses, the conflux losses and the shoot of jet fans in the semi-transverse ventilation system of Er Lang Shan highway tunnel are studied by numerical simulation. Part resistance coefficients that numerical simulation of the semi-transverse Ventilation under various work condition needs are obtained.

Abstract: The Hall resistivity in the layers of Al_xGa_1-xAs/Al_0.32Ga_0.68As is found to show plateaus at certain fractions which depend on the effective charge. The Hall resistivity formula ρ_xy=h/e² has been modified to ρ_xy=h/[(1/2) ge²] so that the effective charge of the electron becomes, e*=(1/2) ge. The plateaus occur at the effective charge determined by g = (2j+1)/(2l+1). Some of the plateaus are explained to arise from the g values while some others require the use of Landau levels. The flux quantization is modified to include the effect of spin. When the samples are doped with aluminium, the clusters of Al atoms occur in the GaAs resulting into electron clusters in which the spin is NS with S=1/2 and N=101. The electron clusters form a temperature dependent plateau in the Hall resistivity.

Abstract: In this paper, the reduced master equation which is a fast simulation method of spin dependent transport in ferromagnetic single electron transistors is presented, for first time. This simulation method follows steady state master equation in which all charge states of the system are considered, whereas charge states are decreased in reduced master equation. This method is based on two degrees of electron freedom which are charge and spin. This is applied in the condition that orthodox tunneling theory is applicable to calculate the tunneling rate of electrons through barriers. The comparison between the I-V characteristics of a ferromagnetic single-electron transistor by following the reduced and full master equation methods for different main parameters of these transistors show that the results are exactly the same at low bias voltages. Consequently, the reduced master equation method is not only more simplified and improves the speed of numerical simulation, but also the modeling results are as accurate as the results of the full maser equation method at low bias conditions.

Abstract: An effort is made to develop a computer programme by using C++ language to generate the orbits of the planets of the solar system in a three dimentional view. The programme presented makes the orbits and one can see the rotations. It is also possible to make the same programme in 2D.

Abstract: Underground gas storages （UGS） are widely used to store the excess of produced natural gas during periods of low demand, and relieve the pressure during periods of high demand. Depleted natural gas reservoir is generally the best choice against others. Proper selection of a depleted gas reservoir is essential to the succession, steady and reliability of UGS in the long run. Sealing capacity of caprock is an important index for measuring the performance of gas storage reservoir. In order to analysis feasibility of UGS in JB area, the development characteristics of caprock were studied, the sealing gas effectiveness of caprock was evaluated. it was concluded that the main caprock was the formation of evaporative carbonate platform, and the breakthrough pressure of cap rock was high. The cap rocks with good sealing capacity were distributed in the area between S224 well and S39 well. The sealing ability was comprehensively evaluated by use of the development features and sealing capacity of caprock.

Abstract: A methodology to fabricate high aspect ratio (HAR) SU-8 micro structures on piezoelectric and metallic substrates is presented. In this work, several fabrication trials were carried out to optimize the SU-8 fabrication process. The fabrication recipe mentioned in the SU-8 (Microchem, USA) datasheet is employed for the initial fabrication trials. The SU-8 structures (micropillars) fabricated during these trials resulted in poor bonding with the surface of piezoelectric substrate. In the later trials a thin film of OmniCoat (Microchem, USA) is coated over the substrate before coating the SU-8 film to improve the adhesion quality of the SU-8 micropillars to the substrate. The fabrication methodology used during the trails and results on the quality of the fabricated HAR SU-8 pillars are discussed in the paper.

Abstract: At present, the research on the radiation-harden ability is the hot spot in the field of aerospace devices. In the paper, one commercial D flip-flop chain and one radiation-harden D flip-flop chain are chosen to be tested on the five conditions of different work frequency in the range of 100k~100M. The test would help us to study the frequency effect on SEE. The result shows that when the work frequency increases 10³ times, the upset threshold of commercial D flip-flop chain is almost unchanged, but the saturation cross section of the single event upset (SEU) increases about 7.13 times. Compared with radiation-harden D flip-flop chain, the reinforced chain has higher upset threshold, lower upset saturation cross section, and the saturation cross section increases about 3.71 times when the work frequency increases 10³ times.

Abstract: In the present work, a numerical investigation has been performed to study the thermal behavior of a flow through a pulsed detonation thermal spray device that employs a hydrogen-air mixture. In this device, a detonation wave travels inside a detonation tube and eventually exits the tube and impinges against a substrate. Two types of substrates have been investigated, namely, a sphere and a flat-plate. The present model is based on solving the two dimensional, axisymetric Euler reactive flow equations with temperature-dependent specific heats. A global single step finite rate reaction has been considered. The present results demonstrate the effects of two main parameters on the thermal performance of the device under consideration. These parameters are: the size and shape of the substrate, and the stand off distance.